1. Field of the Invention
This invention relates to a syringe assembly, and, more specifically, relates to such an assembly which is adapted to have improved safety and efficiency features when used in a medical environment, as well as other environments.
2. Description of the Prior Art
Various types of syringe assemblies for receiving and dispensing medication as well as other materials have been known. In general, the medication or other material is introduced into the hollow barrel portion either by receiving the same through the needle which communicates with the barrel interior, or by means of a frangible container, such as an ampule, which is placed within the hollow barrel. Applying pressure to the plunger causes the medication or other material to be expressed through the hollow needle.
It has been known to provide means for controlling the dosage of medicinal compositions dispensed by a hypodermic syringe through the use of adjustable means. See U.S. Pat. Nos. 2,554,451 and 2,578,812.
Various means have been suggested for controlling the depth of needle penetration into a patient. U.S. Pat. No. 3,434,473 discloses multiple closures, with the removal of each resulting in an additional amount of the needle being exposed. U.S. Pat. Nos. 1,436,707 and 2,091,438 disclose the use of mechanical stop members secured directly to the needle.
A number of disclosures provide means for detecting seepage of blood through the needle bore. See U.S. Pat. Nos. 2,556,331, 2,568,346 and 3,739,780.
U.S. Pat. No. 3,527,216 discloses a multi-compartment mixing chamber wherein the needle is said to serve as a means for fracturing seals to initially mix components which are sealed separately and ultimately to administer the mixture.
There remains a very substantial need for a syringe assembly which will easily and effectively permit adjustment of depth of needle penetration while resisting undesired accidental puncture wounds during syringe handling, use and disposal.